LD5525GL datasheet(11/16 Pages) LEADTREND

11 / 16 page

LD5525

06/30/2015

Leadtrend Technology Corporation

www.leadtrend.com.tw

LD5525-DS-00 June 2015

VCC

GND

LD5525

RC filter is needed whenever the negative

spike is exceed - 0.3 V or the total spike

width is over 350 nS LEB period.

OUT

Fig. 10

Over Voltage Protection on VCC pin

(VCC OVP)

– Auto Recovery

The VGS ratings of the nowadays power MOSFETs are

often limited up to max. 28.5V. To prevent the VGS from

the fault condition, LD5525 is implemented with an OVP

function on VCC.

Whenever the VCC voltage is higher

than the OVP threshold voltage, the output gate drive

circuit will be shutdown simultaneously thus to stop the

switching of the power MOSFET until the next UVLO(ON).

The VCC OVP function in LD5525 is an auto-recovery

type protection. The Fig. 11 shows its operation.

On the other hand, if the OVP condition is removed, the

VCC level will get back to normal level and the output will

automatically return to the normal operation.

VCC

UVLO(on)

UVLO(off)

OVP Tripped

OUT

Switching

Non-Switching

OVP Level

Fig.11

Over Load Protection (OLP)

– Auto

Recovery

To protect the circuit from damage due to over-load

condition and short or open-loop condition, the LD5525 is

implemented with smart OLP function. It also features

auto

–recovery function, see Fig. 12 for the waveform. In

case of fault condition, the feedback system will force the

voltage loop toward the saturation and then pull the

voltage high on COMP pin (VCOMP).

When the VCOMP

ramps up to the OLP threshold of 4.5V and continues over

OLP delay time, the protection will be activated and then

turn off the gate output to stop the switching of power

circuit.

With the protection mechanism, the average input power

will be minimized to remain the component temperature

and stress within the safe operating area.

VCC

UVLO(on)

UVLO(off)

COMP

OLP

4.5V

OUT

OLP delay time

Switching

Non-Switching

OLP trip Level

UVLO(off)

OLP Reset

Fig. 12

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